/* Copyright  2009
   @Author
   Richard Changde Yin            e-mail yinchangde@hotmail.com

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
   
/**
 * @filename: second.cc
 */ 

#include "server_includes.h"
#include CSTDINT_H
#include "temporal.h"
#include "error.h"
#include "function/time/second.h"

int64_t Item_func_second::val_int()
{
  assert(fixed);

  if (args[0]->is_null())
  {
    /* For NULL argument, we return a NULL result */
    null_value= true;
    return 0;
  }

  /* 
   * Because of the ridiculous way in which COLLAPSAR handles
   * TIME values (it does implicit integer -> string conversions
   * but only for DATETIME, not TIME values) we must first 
   * try a conversion into a TIME from a string.  If this
   * fails, we fall back on a DATETIME conversion.  This is
   * necessary because of the fact that DateTime::from_string()
   * looks first for DATETIME, then DATE regex matches.  6 consecutive
   * numbers, say 231130, will match the DATE regex YYMMDD
   * with no TIME part, but COLLAPSAR actually implicitly treats
   * parameters to SECOND(), HOUR(), and MINUTE() as TIME-only
   * values and matches 231130 as HHmmSS!
   *
   * Oh, and Brian Aker MADE me do this. :) --JRP
   */
  collapsar::Time temporal_time;
  
  char time_buff[COLLAPSAR_MAX_LENGTH_DATETIME_AS_STRING];
  String tmp_time(time_buff,sizeof(time_buff), &my_charset_utf8_bin);
  String *time_res= args[0]->val_str(&tmp_time);
  if (! temporal_time.from_string(time_res->c_ptr(), time_res->length()))
  {
    /* 
     * OK, we failed to match the first argument as a string
     * representing a time value, so we grab the first argument 
     * as a DateTime object and try that for a match...
     */
    collapsar::DateTime temporal_datetime;
    Item_result arg0_result_type= args[0]->result_type();
    
    char buff[COLLAPSAR_MAX_LENGTH_DATETIME_AS_STRING];
    String tmp(buff,sizeof(buff), &my_charset_utf8_bin);
    String *res;    
    
    switch (arg0_result_type)
    {
      case DECIMAL_RESULT: 
        /* 
         * For doubles supplied, interpret the arg as a string, 
         * so intentionally fall-through here...
         * This allows us to accept double parameters like 
         * 19971231235959.01 and interpret it the way MySQL does:
         * as a TIMESTAMP-like thing with a microsecond component.
         * Ugh, but need to keep backwards-compat.
         */
      case STRING_RESULT:
        {
          res= args[0]->val_str(&tmp);
          
          if (! temporal_datetime.from_string(res->c_ptr(), res->length()))
          {
            /* 
            * Could not interpret the function argument as a temporal value, 
            * so throw an error and return 0
            */
            my_error(ER_INVALID_DATETIME_VALUE, MYF(0), res->c_ptr());
            return 0;
          }
        }
        break;
      case INT_RESULT:
        if (temporal_datetime.from_int64_t(args[0]->val_int()))
          break;
        /* Intentionally fall-through on invalid conversion from integer */
       default:
        {
          /* 
          * Could not interpret the function argument as a temporal value, 
          * so throw an error and return 0
          */
          null_value= true;


          res= args[0]->val_str(&tmp);

          my_error(ER_INVALID_DATETIME_VALUE, MYF(0), res->c_ptr());
          return 0;
        }
    }
    return (int64_t) temporal_datetime.seconds();
  }
  return (int64_t) temporal_time.seconds();
}

